waterproof sheet connection structure
The use of a water-insoluble butyl rubber connecting medium with adhesive layers addresses the issue of shape loss and shifting in waterproof sheet connections, enhancing work accuracy and efficiency during construction, especially in wet conditions.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- VOLCLAY JAPAN CO LTD
- Filing Date
- 2025-01-17
- Publication Date
- 2026-07-30
AI Technical Summary
Conventional waterproof sheet connection structures using water-soluble binders and clay-based materials are prone to shape loss and washing away during wet conditions, leading to decreased work accuracy and efficiency, especially on slopes during rainy weather.
A connection structure using a strip-shaped connecting medium made of water-insoluble butyl rubber with adhesive layers on both sides, interposed between waterproof sheets, which penetrates woven or non-woven fabrics to maintain shape and seal gaps effectively.
The connection structure maintains work accuracy and efficiency by preventing shifting of waterproof sheets and ensuring watertightness even in wet conditions, reducing workload during construction.
Smart Images
Figure 2026123572000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a connection structure of a water barrier sheet.
Background Art
[0002] For example, as shown in the following Patent Document 1, in the construction of a water storage tank or the like, a water stop structure that lays a water barrier sheet on a slope with a slope surface shaped by slope grading to prevent water leakage has been widely known. Such a conventional water stop structure lays a plurality of water barrier sheets on a horizontal surface or a slope to be water-barriered (hereinafter referred to as a laying surface). However, at the joint portion (overlapping portion) of the water barrier sheets, measures are required to prevent water leakage from the gap. Therefore, conventionally, there are various connection structures of water barrier sheets that take measures to prevent water leakage at the joint portion of the water barrier sheets. For example, those described in the following Patent Document 2 and the following Patent Document 3 are known.
[0003] Patent Document 2 discloses a connection structure of a water barrier sheet in which a protective layer made of a woven fabric or a non-woven fabric of the water barrier sheet is impregnated with a water-insoluble adhesive over a predetermined range, and thereby the joint portion of the water barrier sheets is adhered. According to the technique described in this Patent Document 2, the gap between the water barrier sheets can be sealed by the water-insoluble adhesive impregnated in the protective layer of the water barrier sheet, and water leakage can be prevented. However, in the connection structure of the water barrier sheet described in Patent Document 2, at the time of construction, it takes time to apply an adhesive between one water barrier sheet to be connected and the other water barrier sheet.
[0004] On the other hand, Patent Document 3 discloses a connection structure of a water barrier sheet in which a strip-shaped connecting medium (sealing pack) mainly made of a clay-based material is interposed at the joint portion of the water barrier sheets. According to the technique described in this Patent Document 3, the gap between the water barrier sheets can be sealed by the water absorption swelling property of the connecting medium, and water leakage can be prevented. Furthermore, since the water barrier sheets can be connected by a simple operation of installing the connecting medium along the connection portion (joint portion) of the water barrier sheets, the work burden during construction can be reduced.
Prior Art Documents
[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-13345 [Patent Document 2] Japanese Patent Publication No. 2021-59909 [Patent Document 3] Japanese Patent Publication No. 2019-55382 [Overview of the project] [Problems that the invention aims to solve]
[0006] However, the connection structure for the waterproof sheet described in Patent Document 3 uses a water-soluble binder and a water-soluble protective sheet as the connecting medium. As a result, the connecting medium is prone to losing its shape when wet during construction, and is also easily washed away by water. Consequently, in situations where the connecting medium is likely to get wet, such as during construction in rainy weather, this could lead to a decrease in work accuracy and efficiency. In particular, when laying a waterproof sheet on a slope, the waterproof sheet is more likely to shift than on a horizontal surface, and this problem becomes even more pronounced in rainy weather as water flows down the slope. Patent Document 3 also mentions an embodiment in which a clay-based material is packed into a permeable sealing bag to form the connecting medium. However, according to this embodiment, another problem arises: the watertightness is reduced due to the permeable sealing bag.
[0007] Thus, while the conventional waterproof sheet connection structure described in Patent Document 3 can reduce the workload, it may lead to a decrease in work accuracy and efficiency during construction in situations where the connecting medium is likely to get wet, such as during rainy weather.
[0008] Therefore, the present invention aims to provide a connection structure for a waterproof sheet that can reduce the workload during construction while preventing a decrease in work accuracy and work efficiency, even when the connecting medium is prone to getting wet. [Means for solving the problem]
[0009] To achieve the above objective, the first invention is: A connection structure for a connection part formed by overlapping waterproof sheets, The aforementioned connection portion has a strip-shaped connecting medium interposed between the waterproof sheets. The connecting medium comprises a connecting medium body made of water-insoluble butyl rubber as a base material, and adhesive layers having adhesive properties provided on both sides of the connecting medium body. The aforementioned waterproof sheet has a woven or non-woven fabric on its surface. The present invention provides a connecting structure characterized in that the adhesive layer is composed of a rubber-based adhesive that penetrates woven or nonwoven fabrics.
[0010] According to the first invention described above, since the connecting medium body is based on water-insoluble butyl rubber, it can swell without significantly damaging its shape even after contact with moisture. As a result, even in situations where the connecting medium is prone to getting wet, it is possible to provide a connection structure for waterproof sheets that reduces the workload during construction while preventing a decrease in work accuracy and work efficiency. Furthermore, once the connecting medium is attached to the waterproof sheet, it penetrates the nonwoven or woven fabric of the waterproof sheet, exhibiting watertightness and effectively preventing the connecting waterproof sheets from shifting, thereby further improving work accuracy and work efficiency during construction.
[0011] The second invention, in addition to the configuration of the first invention, The connecting medium is disposed on the upper surface of the waterproof sheet to be connected, and The connecting medium is characterized in that it is arranged such that its end protrudes from the end of the waterproof sheet to be connected, towards the waterproof sheet side.
[0012] According to the second invention described above, in addition to the effects of the first invention described above, the gaps between the water-impermeable sheets can be sealed more effectively, thereby achieving high watertightness.
[0013] The third invention is, in addition to the configuration of the first or the second invention, the water barrier sheet is formed by laminating a non-woven fabric, granular bentonite, and a woven fabric in this order from the bottom, furthermore, it is characterized in that a water-impermeable layer provided with a notch adapted to the width of the connection part is provided on the lower surface of the non-woven fabric.
[0014] According to the third invention, in addition to the effects of the first or the second invention, when the connection medium is adhered to the water barrier sheet, the adhesive layer penetrates into the non-woven fabric or the woven fabric of the water barrier sheet to exhibit water tightness, and for portions where the connection medium is not adhered, better water barrier can be achieved by the water-impermeable layer.
Advantages of the Invention
[0015] According to the present invention, it is possible to provide a connection structure of a water barrier sheet that can reduce the work burden during construction and prevent a decrease in work accuracy and work efficiency while the connection medium is in a situation where it is likely to get wet.
Brief Description of the Drawings
[0016] [Figure 1] FIG. 1 is a schematic perspective view for explaining the schematic configuration of a water barrier sheet connection structure according to a preferred embodiment of the present invention. [Figure 2] FIG. 2 is the same schematic perspective view. [Figure 3] FIG. 3(a) is a perspective view of the connection medium before use in FIG. 1, and FIG. 3(b) is a perspective view for explaining the connection structure of the connection part. [Figure 4] FIGS. 4(a) and 4(b) are cross-sectional views for explaining the connection method of the connection part. [Figure 5] FIGS. 5(a) and 5(b) are cross-sectional views for explaining another connection method of the connection part. [Figure 6] FIG. 6 is a longitudinal cross-sectional view of a water barrier sheet according to a preferred embodiment of the present invention. [Figure 7] FIG. 7 is a longitudinal cross-sectional view of a connection medium according to a preferred embodiment of the present invention. [Figure 8] Figure 8 is a longitudinal sectional view of the connecting portion 30 in FIG. 1. [Figure 9] Figure 9 is a longitudinal sectional view of a water shielding sheet according to another embodiment. [Figure 10] Figure 10 is a longitudinal sectional view of a connecting portion of a water shielding sheet according to another embodiment. [Figure 11] Figure 11 is a schematic sectional view for explaining an example of use of a connecting medium around a drain pipe. [Figure 12] Figure 12 is a longitudinal sectional view showing the configuration of a connecting medium according to another embodiment. [Figure 13] Figure 13 is a schematic sectional view for explaining an example of use in which the connecting medium according to the present embodiment and the connecting medium according to another embodiment are combined. [Figure 14] Figures 14(a) and 14(b) are explanatory diagrams for explaining a method of reinforcing a connecting medium.
Mode for Carrying Out the Invention
[0017] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIGS. 1 and 2 are schematic perspective views for explaining the schematic configuration of a water shielding sheet connection structure according to a preferred embodiment of the present invention. FIGS. 1 and 2 illustrate a state in which a plurality of water shielding sheets 20 are laid along a subgrade 10 having a laying surface. More specifically, FIG. 1 shows a state in which a plurality of water shielding sheets 20 (three in the illustrated example) are connected to each other, and FIG. 2 shows a state before connection. For convenience of explanation, in this specification, directions are defined as shown in FIG. 1. That is, the longitudinal direction of the water shielding sheet is defined as the front-rear direction, and the direction perpendicular to the front-rear direction is defined as the left-right direction.
[0018] <1. Schematic Configuration of Water Shielding Sheet Connection Structure> The shape of the base structure 10 is not particularly limited, but in this embodiment, as an example, it is a stepped, sloping surface with a series of small steps. More specifically, as shown in Figures 1 and 2, the base structure 10 is formed so that sloped sections 10a and level horizontal sections 10b alternate. The base structure 10 is, for example, a slope formed for a reservoir, and is constructed by layering soil with geogrid, crushed stone, nonwoven fabric, and sand.
[0019] A connection section 30 is formed between multiple waterproof sheets 20 laid on the base 10, with the waterproof sheets 20 overlapping each other. Furthermore, as shown in Figure 2, a connecting medium 40 is interposed between the waterproof sheets 20 in the connection section 30, along the longitudinal direction of the connection section 30, to connect the waterproof sheets 20 together. The connection section 30 and the connecting medium 40 will be described later. Additionally, anchors K are driven into the waterproof sheets 20 at predetermined intervals along the longitudinal direction of the connection section 30, thus fixing the waterproof sheets 20 to the base 10. Anchors K are also driven into other appropriate locations on the waterproof sheets 20 to further secure them.
[0020] These anchors K are, for example, installed at intervals of 0.5 to 2 meters, and it is preferable to narrow the spacing as the slope of the embankment 10a becomes steeper. Furthermore, various types of anchors K can be used depending on the situation, such as L-shaped, U-shaped, or nails.
[0021] As shown in Figure 2, before connecting the waterproof sheets 20, the connection side of the waterproof sheet 20 to be connected in the short direction has its end folded back in the direction of F1 in the figure, forming a folded portion 21, and a connecting medium 40 is placed on the upper surface of the connection side end of the waterproof sheet 20 to be connected. The upper parts of the multiple waterproof sheets 20 are fixed to the base 10 by retaining clips 50 to prevent slippage.
[0022] <2. Outline of the connection section> Figure 3(a) is a perspective view of the connecting medium before use as shown in Figure 1; Figure 3(b) is a perspective view illustrating the connection structure of the connecting part; Figures 4(a) and 4(b) are cross-sectional views illustrating the connection method of the connecting part; and Figures 5(a) and 5(b) are cross-sectional views illustrating another connection method of the connecting part.
[0023] As shown in Figure 3(a), the connecting medium 40 before use is wound into a tape shape, and an anti-sticking sheet 41 is provided on the surface of the connecting medium 40 to prevent the connecting mediums 40 from sticking to each other. When using, the connecting medium 40 can be attached to the waterproof sheet 20 by unwinding it and peeling off the anti-sticking sheet 41 from the connecting medium 40.
[0024] As shown in Figures 3(b), 4(a), and 4(b), the connection structure of the connection portion 30 is such that a connecting medium 40 is placed on the upper surface of the connection-side end of the waterproof sheet 20 to be connected, and the folded portion 21 of the waterproof sheet 20 to be connected is folded back in the direction of arrow F2 so as to cover the connecting medium 40. In this way, the connecting medium 40 is interposed between the waterproof sheets 20 to form the connection portion 30.
[0025] In this case, as shown in Figures 4(a) and 4(b), the width Db of the connecting portion 30 is provided to be larger than the width Da of the connecting medium 40. For example, the width Da is 50 mm and the width Db is 20 mm. Alternatively, the connecting medium 40 may be positioned so that the end of the connecting medium 40 aligns with the end of the waterproof sheet 20 to be connected, or, as shown in Figures 5(a) and 5(b), the connecting medium 40 may be positioned so that its end protrudes toward the waterproof sheet 20 to be connected. This allows for a more favorable sealing of the gaps between the waterproof sheets 20.
[0026] Figure 6 is a longitudinal cross-sectional view of a water-impermeable sheet 20 according to a preferred embodiment of the present invention. As shown in Figure 6, the waterproof sheet 20 according to a preferred embodiment of the present invention is formed by laminating a nonwoven fabric 20a, granular bentonite (Na type) 20b, and woven fabric 20c in that order from bottom to top, and is reinforced by providing a plurality of needle punches 20d that penetrate these layers at predetermined intervals.
[0027] Figure 7 is a longitudinal cross-sectional view of the connecting medium 40 according to a preferred embodiment of the present invention. Figure 8 is a longitudinal cross-sectional view of the connecting portion 30. As shown in Figure 7, the connecting medium 40 has an adhesive layer 40n on both sides of a water-impermeable connecting medium body 40a.
[0028] The connecting medium body 40a is formed into a strip (tape) shape by kneading bentonite, butyl rubber, hydrocarbon resin, and process oil with a non-water-soluble butyl rubber base material and extruding it with a predetermined metal fitting. Preferably, the bentonite content in the connecting medium body 40a is in the range of 50-70% by mass, the butyl rubber content is in the range of 25-40% by mass, the hydrocarbon resin content is in the range of 2.5-5% by mass, and the process oil content is in the range of 2.5-5% by mass. Because this connecting medium body 40a is based on non-water-soluble butyl rubber, it can swell without significantly damaging its shape even after contact with moisture. As a result, even in situations where the connecting medium 40 is likely to get wet, it is possible to provide a waterproof sheet connecting structure that reduces the workload during construction while preventing a decrease in work accuracy and work efficiency. In addition to butyl rubber, non-water-soluble silicone rubber, natural rubber, isoprene rubber, etc. can also be used.
[0029] The adhesive layer 40n is composed of a rubber-based adhesive that penetrates woven and nonwoven fabrics, and can be, for example, a butyl-based, acrylic-based, urethane-based, or silicone-based adhesive. As shown in Figure 8, when the connecting medium 40 is attached to the waterproof sheet 20, the adhesive layer 40n penetrates the nonwoven fabric 20a or woven fabric 20c of the waterproof sheet 20, providing watertightness while effectively preventing the connecting waterproof sheets 20 from shifting, thereby improving work accuracy and efficiency during construction. The adhesive layer 40n can be provided on only one side of the connecting medium body 40a, but it is preferable to provide it on both sides from the viewpoint of improving watertightness.
[0030] <3. Regarding another embodiment> Figure 9 is a longitudinal cross-sectional view of a waterproof sheet 20 according to another embodiment. Figure 10 is a longitudinal cross-sectional view of a connecting portion 30 of the waterproof sheet 20 according to another embodiment. The waterproof sheet 20 according to another embodiment has a structure in which a non-permeable layer 20e made of a non-permeable high-density polyethylene sheet is laminated (layered) to the lower surface of a nonwoven fabric 20a. Furthermore, a notch is provided in the non-permeable layer 20e at one end of the waterproof sheet 20 to match the width Db of the connecting portion 30. As a result, as shown in Figure 10, when the connecting medium 40 is attached to the waterproof sheet 20, it penetrates into the nonwoven fabric 20a or woven fabric 20c of the waterproof sheet 20, exhibiting watertightness, while in areas where the connecting medium 40 is not attached, the non-permeable layer 20e provides good waterproofing.
[0031] Figure 11 is a schematic cross-sectional view illustrating an example of the use of the connecting medium 40 around the drain pipe 60. As shown in Figure 11, when a drain pipe 60 is present in the base 10 (slope portion 10a), the waterproof sheet 20 can be fixed to the tip of the drain pipe 60 with a stainless steel band 22, and a connecting medium 40 can be placed along the periphery of the base of the drain pipe 60, and the waterproof sheet 20 can be attached to it, thereby ensuring good watertightness around the drain pipe 60.
[0032] Figure 12 is a longitudinal cross-sectional view showing the configuration of a connecting medium 40' according to another embodiment. In another embodiment, the connecting medium 40', as shown in Figure 12, has an adhesive layer 40n on the lower surface of a water-impermeable connecting medium body 40a, and a water-impermeable base layer 40m on the upper surface. The base layer 40m can be made of, for example, polyethylene net, polyethylene film, etc. This base layer 40m allows for good treatment of the edges of the sheet around structures and pipes, and for areas where the sheet will be exposed for a long period after construction. For example, in the example of use shown in Figure 11, the connecting medium 40' of this other embodiment may be used instead of the connecting medium 40 of this embodiment.
[0033] Figure 13 is a schematic cross-sectional view illustrating an example of using a combination of the connecting medium 40 according to this embodiment and the connecting medium 40' according to another embodiment. Figure 13 shows an example of attaching a vulcanized rubber sheet to a concrete structure with a roughly L-shaped cross-section to provide waterproofing. As shown in Figure 13, the connecting medium 40 according to this embodiment and the connecting medium 40' according to another embodiment can be used in combination depending on the application.
[0034] Figures 14(a) and 14(a) are explanatory diagrams illustrating a method for reinforcing the connecting medium 40. As shown in Figures 14(a) and 14(a), the connecting medium 40 may be reinforced by placing a woven fabric 42 between two upper and lower connecting mediums 40, 40. This further improves the prevention of unintended deformation of the connecting medium 40 during construction. [Explanation of Symbols]
[0035] 10 Substrate 10a Slope section 10b Horizontal part 20 Waterproof sheet 20a non-woven fabric 20b Granular Bentonite 20c woven fabric 20d Needle Punch 20e Impermeable layer 21 Folded section 30 Connection part 40 Connection media 40' Connecting medium (another embodiment) 40a Main unit of the connected media 40n adhesive layer 40m base layer 41. Anti-sticking sheet 42 Woven fabric 50 Legal fastening 60 Drain pipe K Anchor
Claims
1. A connection structure for a connection part formed by overlapping waterproof sheets, The aforementioned connection portion has a strip-shaped connecting medium interposed between the waterproof sheets. The connecting medium comprises a connecting medium body made of water-insoluble butyl rubber as a base material, and adhesive layers having adhesive properties provided on both sides of the connecting medium body. The aforementioned waterproof sheet has a woven or non-woven fabric on its surface. The connecting structure is characterized in that the adhesive layer is composed of a rubber-based adhesive that penetrates woven or nonwoven fabrics.
2. The connecting medium is disposed on the upper surface of the waterproof sheet to be connected, and The connection structure according to claim 1, characterized in that the end of the connecting medium is arranged such that it protrudes from the end of the waterproof sheet to be connected, toward the waterproof sheet to be connected.
3. The aforementioned waterproof sheet is made by laminating nonwoven fabric, granular bentonite, and woven fabric in that order from bottom to top. Furthermore, the connection structure according to claim 1 or 2 is characterized by having a non-permeable layer on the lower surface of the nonwoven fabric, with a notch provided to match the width of the connection portion.